Anterior cervical fixation plate for fixating portions of a cervical spine to facilitate bone fusion

ABSTRACT

Various implementations include an anterior cervical fixation plate for fixating portions of a cervical spine to facilitate bone fusion. The plate includes a first portion, a second portion, and a bridge. A first surface of the first portion and a first surface of the second portion each define two fastener openings extending from the first surface of the first portion to a second surface of the first portion. The first side and the second side of the centrally located bridge each extend from the second side of the first portion to the first side of the second portion. The second side of the first portion, the first side of the second portion, and the first side of the bridge define a first window. The second side of the first portion, the first side of the second portion, and the second side of the bridge define a second window.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. provisional patentapplication No. 62/676,649, filed on May 25, 2018, and entitled“ANTERIOR CERVICAL FIXATION PLATE SYSTEM,” the disclosure of which isexpressly incorporated herein by reference in its entirety.

BACKGROUND

Anterior cervical fixation plates are spine implants that are used tofixate portions of a cervical spine to facilitate bone fusion. Theplates include fasteners (typically screws) for affixing the plate tomultiple vertebral bodies, which facilitates bone fusion by stabilizingsections of the cervical spine following anterior cervical discectomyand corpectomy procedures.

Before an anterior cervical fixation plate can be affixed to the spineof a patient, the tissue surrounding the spine must be retracted toexpose enough of the vertebral bodies to insert and position the plate.Further, any osteophytes formed at the bases of the vertebral bodiesmust be removed so that the plate can be placed flat on the vertebrae.However, excessive retraction of the tissue surrounding the spine cancause dysphagia in the patient and can lead to longer recovery times.The removal of osteophytes from the vertebrae can also lead to longersurgery time and longer recovery.

Thus, a need exists for an anterior cervical fixation plate that can beimplanted with less retraction of tissue and less removal ofosteophytes.

SUMMARY

Anterior cervical fixation plates for fixating portions of a cervicalspine to facilitate bone fusion are described herein. An exampleanterior cervical fixation plate includes a first portion, a secondportion, and a bridge. The first portion has a first surface, a secondsurface opposite and spaced apart from the first surface of the firstportion, a first side, a second side opposite and spaced apart from thefirst side of the first portion, a third side, a fourth side oppositeand spaced apart from the third side of the first portion, and a firstaxis extending from the third side of the first portion to the fourthside of the first portion. The first surface of the first portiondefines a first fastener opening and a second fastener opening. Each ofthe first fastener opening and the second fastener opening are alignedalong the first axis. Each of the first fastener opening and the secondfastener opening extend from the first surface of the first portion tothe second surface of the first portion.

The second portion has a first surface, a second surface opposite andspaced apart from the first surface of the second portion, a first side,a second side opposite and spaced apart from the first side of thesecond portion, a third side, a fourth side opposite and spaced apartfrom the third side of the second portion, and a second axis extendingfrom the third side of the second portion to the fourth side of thesecond portion. The first surface of the second portion defines a thirdfastener opening and a fourth fastener opening. Each of the thirdfastener opening and the fourth fastener opening are aligned along thesecond axis. Each of the third fastener opening and the fourth fasteneropening extend from the first surface of the second portion to thesecond surface of the second portion.

The bridge has a first surface, a second surface opposite and spacedapart from the first surface of the bridge, a first side, and a secondside opposite and spaced apart from the first side of the bridge. Thebridge is centrally located between the first portion and the secondportion, and the first side and the second side of the bridge eachextend from the second side of the first portion to the first side ofthe second portion. The second side of the first portion, the first sideof the second portion, and the first side of the bridge define a firstwindow. The second side of the first portion, the first side of thesecond portion, and the second side of the bridge define a secondwindow.

Other systems, methods, features and/or advantages will be or may becomeapparent to one with skill in the art upon examination of the followingdrawings and detailed description. It is intended that all suchadditional systems, methods, features and/or advantages be includedwithin this description and be protected by the accompanying claims.

BRIEF DESCRIPTION OF DRAWINGS

Example features and implementations are disclosed in the accompanyingdrawings. However, the present disclosure is not limited to the precisearrangements and instrumentalities shown. Similar elements in differentimplementations are designated using the same reference numerals.

FIG. 1A is a top view of an anterior cervical fixation plate, accordingto one implementation. FIG. 1B is a side view of the anterior cervicalfixation plate of FIG. 1A.

FIG. 2A is a top view of an anterior cervical fixation plate, accordingto another implementation. FIG. 2B is a side view of the anteriorcervical fixation plate of FIG. 2A.

FIG. 3 is a perspective view of the anterior cervical fixation plate ofFIGS. 1A and 1B affixed to a spine with the fasteners in a convergingorientation.

FIG. 4 is a perspective view of the anterior cervical fixation plate ofFIGS. 1A and 1B affixed to a spine with the fasteners in a divergingorientation.

FIG. 5A is a perspective view of the anterior cervical fixation plate ofFIGS. 1A and 1B with an anti-backout device in the first position. FIG.5B is a perspective view of the anterior cervical fixation plate ofFIGS. 1A and 1B with the anti-backout device in the second position.

DETAILED DESCRIPTION

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art. Methods and materials similar or equivalent to those describedherein can be used in the practice or testing of the present disclosure.As used in the specification, and in the appended claims, the singularforms “a,” “an,” “the” include plural referents unless the contextclearly dictates otherwise. The term “comprising” and variations thereofas used herein is used synonymously with the term “including” andvariations thereof and are open, non-limiting terms. The terms“optional” or “optionally” used herein mean that the subsequentlydescribed feature, event or circumstance may or may not occur, and thatthe description includes instances where said feature, event orcircumstance occurs and instances where it does not. Ranges may beexpressed herein as from “about” one particular value, and/or to “about”another particular value. When such a range is expressed, an aspectincludes from the one particular value and/or to the other particularvalue. Similarly, when values are expressed as approximations, by use ofthe antecedent “about,” it will be understood that the particular valueforms another aspect. It will be further understood that the endpointsof each of the ranges are significant both in relation to the otherendpoint, and independently of the other endpoint. As used herein, theterms “about” or “approximately”, when used in reference to a lineardimension (e.g., width, thickness, etc.), mean within plus or minus 10percentage of the referenced the linear dimension.

The devices and systems disclosed herein provide for anterior cervicalfixation plates for fixating portions of a cervical spine to facilitatebone fusion. The plates have two or more portions and each portion ofthe plate defines at least two fastener openings. In other words, theplate has two points of fixation per level such that it accommodates twofasteners (e.g., screws) per vertebral body. Each set of adjacentportions of the plate are adjoined by a bridge extending between theportions. Because the plate is manufactured from a strong material suchas an alternative medical grade material as described herein, the plateis designed with smaller dimensions. The smaller plate allows the plateto be affixed to the spine of a patient with less disruption of tissue,lowering the risk of surgical complications and shortening recoverytimes.

Various implementations include an anterior cervical fixation plate forfixating portions of a cervical spine to facilitate bone fusion. Theplate includes a first portion, a second portion, and a bridge. Thefirst portion has a first surface, a second surface opposite and spacedapart from the first surface of the first portion, a first side, asecond side opposite and spaced apart from the first side of the firstportion, a third side, a fourth side opposite and spaced apart from thethird side of the first portion, and a first axis extending from thethird side of the first portion to the fourth side of the first portion.The first surface of the first portion defines a first fastener openingand a second fastener opening. Each of the first fastener opening andthe second fastener opening are aligned along the first axis. Each ofthe first fastener opening and the second fastener opening extend fromthe first surface of the first portion to the second surface of thefirst portion.

The second portion has a first surface, a second surface opposite andspaced apart from the first surface of the second portion, a first side,a second side opposite and spaced apart from the first side of thesecond portion, a third side, a fourth side opposite and spaced apartfrom the third side of the second portion, and a second axis extendingfrom the third side of the second portion to the fourth side of thesecond portion. The first surface of the second portion defines a thirdfastener opening and a fourth fastener opening. Each of the thirdfastener opening and the fourth fastener opening are aligned along thesecond axis. Each of the third fastener opening and the fourth fasteneropening extend from the first surface of the second portion to thesecond surface of the second portion.

The bridge has a first surface, a second surface opposite and spacedapart from the first surface of the bridge, a first side, and a secondside opposite and spaced apart from the first side of the bridge. Thebridge is centrally located between the first portion and the secondportion, and the first side and the second side of the bridge eachextend from the second side of the first portion to the first side ofthe second portion. The second side of the first portion, the first sideof the second portion, and the first side of the bridge define a firstwindow. The second side of the first portion, the first side of thesecond portion, and the second side of the bridge define a secondwindow.

Various other implementations include an anterior cervical fixationplate for fixating portions of a cervical spine to facilitate bonefusion. The plate includes a first portion, a second portion, and abridge. The first portion has a first surface, a second surface oppositeand spaced apart from the first surface of the first portion, a firstside, a second side opposite and spaced apart from the first side of thefirst portion, a third side, a fourth side opposite and spaced apartfrom the third side of the first portion, and a first axis extendingfrom the third side of the first portion to the fourth side of the firstportion. The first surface of the first portion defines a first fasteneropening and a second fastener opening. Each of the first fasteneropening and the second fastener opening are aligned along the firstaxis. Each of the first fastener opening and the second fastener openingextend from the first surface of the first portion to the second surfaceof the first portion.

The second portion has a first surface, a second surface opposite andspaced apart from the first surface of the second portion, a first side,a second side opposite and spaced apart from the first side of thesecond portion, a third side, a fourth side opposite and spaced apartfrom the third side of the second portion, and a second axis extendingfrom the third side of the second portion to the fourth side of thesecond portion. The first surface of the second portion defines a thirdfastener opening and a fourth fastener opening. Each of the thirdfastener opening and the fourth fastener opening are aligned along thesecond axis. Each of the third fastener opening and the fourth fasteneropening extend from the first surface of the second portion to thesecond surface of the second portion.

The bridge has a first surface, a second surface opposite and spacedapart from the first surface of the bridge, a first side, and a secondside opposite and spaced apart from the first side of the bridge. Thebridge is centrally located between the first portion and the secondportion, and the first side and the second side of the bridge eachextend from the second side of the first portion to the first side ofthe second portion. The plate has a maximum thickness defined as thelargest of the distance from the first surface of the first portion tothe second surface of the first portion, the distance from the firstsurface of the second portion to the second surface of the secondportion, or the distance from the first surface of the bridge to thesecond surface of the bridge. The maximum thickness is 2 mm or less.

Various other implementations include an anterior cervical fixationplate for fixating portions of a cervical spine to facilitate bonefusion. The plate includes a first portion, a second portion, and abridge. The first portion has a first surface, a second surface oppositeand spaced apart from the first surface of the first portion, a firstside, a second side opposite and spaced apart from the first side of thefirst portion, a third side, a fourth side opposite and spaced apartfrom the third side of the first portion, and a first axis extendingfrom the third side of the first portion to the fourth side of the firstportion. The first surface of the first portion defines a first fasteneropening and a second fastener opening. Each of the first fasteneropening and the second fastener opening are aligned along the firstaxis. Each of the first fastener opening and the second fastener openingextend from the first surface of the first portion to the second surfaceof the first portion.

The second portion has a first surface, a second surface opposite andspaced apart from the first surface of the second portion, a first side,a second side opposite and spaced apart from the first side of thesecond portion, a third side, a fourth side opposite and spaced apartfrom the third side of the second portion, and a second axis extendingfrom the third side of the second portion to the fourth side of thesecond portion. The first surface of the second portion defines a thirdfastener opening and a fourth fastener opening. Each of the thirdfastener opening and the fourth fastener opening are aligned along thesecond axis. Each of the third fastener opening and the fourth fasteneropening extend from the first surface of the second portion to thesecond surface of the second portion.

The bridge has a first surface, a second surface opposite and spacedapart from the first surface of the bridge, a first side, and a secondside opposite and spaced apart from the first side of the bridge. Thebridge is centrally located between the first portion and the secondportion, and the first side and the second side of the bridge eachextend from the second side of the first portion to the first side ofthe second portion. The bridge has a bridge width from the first side ofthe bridge to the second side of the bridge. The bridge width is 4.3 mmor less.

FIGS. 1A and 1B show a top view and a side view of an anterior cervicalfixation plate 100 for fixating portions of a cervical spine tofacilitate bone fusion. The plate 100 includes a first portion 110, asecond portion 110′, and a bridge 160. This disclosure contemplates thatthe first portion 110 can attach at a first level (e.g., a firstvertebral body) and the second portion 110′ can attach at a second level(e.g., a second vertebral body), and the bridge 160 connects the firstand second portions 110, 110′. The plate 100 can accommodate fourfasteners 150, e.g., two per level or two per vertebral body.

The first portion 110 of the plate 100 has a first surface 112 and asecond surface 114 opposite and spaced apart from the first surface 112.The first portion 110 also has a first side 120, a second side 122opposite and spaced apart from the first side 120 of the first portion110, a third side 124, and a fourth side 126 opposite and spaced apartfrom the third side 124 of the first portion 110. The first 120, second122, third 124, and fourth sides 126 extend between the first surface112 and the second surface 114. The first portion 110 further includes afirst axis 128 extending from the center of the third side 124 of thefirst portion 110 to the center of the fourth side 126 of the firstportion 110.

The second portion 110′ of the plate 100 has a first surface 112′ and asecond surface 114′ opposite and spaced apart from the first surface112′. The second portion 110′ also has a first side 120′, a second side122′ opposite and spaced apart from the first side 120′ of the secondportion 110′, a third side 124′, and a fourth side 126′ opposite andspaced apart from the third side 124′ of the second portion 110′. Thefirst 120′, second 122′, third 124′, and fourth sides 126′ extendbetween the first surface 112′ and the second surface 114′. The secondportion 110′ further includes a second axis 128′ extending from thecenter of the third side 124′ of the second portion 110′ to the centerof the fourth side 126′ of the second portion 110′.

The bridge 160 has a first surface 162 and a second surface 164 oppositeand spaced apart from the first surface 162 of the bridge 160. Thebridge 160 also has a first side 166 and a second side 168 opposite andspaced apart from the first side 166 of the bridge 160. The bridge 160is centrally located between the first portion 110 and the secondportion 110′, and the first side 166 and the second side 168 of thebridge 160 each extend from the second side 122 of the first portion 110to the first side 120′ of the second portion 110′. The plate 100 shownin FIGS. 1A and 1B has only one bridge 160 structure extending betweenthe first portion 110 and the second portion 110′. As used herein, theterm “bridge” is used to describe all of the structures extendingbetween two adjacent portions. Thus, if a plate has two or more separatestructures extending between two adjacent portions, then the combinationof all of the structures extending between the two adjacent portionsconstitutes a single bridge.

The bridge 160 of the plate 100 has a bridge width 180 as measured fromthe first side 166 of the bridge 160 to the second side 168 of thebridge 160. The plate 100 also has a plate width 182 defined as thelargest of the distance from the third side 124 of the first portion 110to the fourth side 126 of the first portion 110 or the distance from thethird side 124′ of the second portion 110′ to the fourth side 126′ ofthe second portion 110′. As shown in FIGS. 1A and 1B, the bridge width180 is less than the plate width 182. A portion of the second side 122of the first portion 110, a portion of the first side 120′ of the secondportion 110′, and the first side 166 of the bridge 160 define a firstwindow 170, and a portion of the second side 122 of the first portion110, a portion of the first side 120′ of the second portion 110′, andthe second side 168 of the bridge 160 define a second window 172. Whenthe plate 100 is being affixed to portions of a cervical spine 196, thewindows 170, 172 allow the physician to see the intervertebral spacebetween the two vertebrae 198. Thus, the physician can use the windows170, 172 to determine the correct location of the plate 100 beforeaffixing the plate 100.

The first surface 112 of the first portion 110 defines a first fasteneropening 130 and a second fastener opening 140. Each of the firstfastener opening 130 and the second fastener opening 140 are alignedalong the first axis 128 such that first axis 128 passes through atleast a portion of the fastener openings 130, 140. Each of the firstfastener opening 130 and the second fastener opening 140 extend from thefirst surface 112 of the first portion 110 to the second surface 114 ofthe first portion 110. The first fastener opening 130 and the secondfastener opening 140 each have a first section 132, 142 with a firstdiameter 134, 144 and a second section 136, 146 with a second diameter138, 148 that is smaller than the first diameter 134, 144. The firstsection 132, 142 of each fastener opening 130, 140 is closer than thesecond section 136, 146 to the first surface 112 of the first portion110. Because the first diameters 134, 144 are larger than the seconddiameters 138, 148, the intersection of the first section 132, 142 andthe second section 136, 146 of each fastener opening 130, 140 forms alip 139, 149.

The first surface 112′ of the second portion 110′, similarly, defines athird fastener opening 130′ and a fourth fastener opening 140′. Each ofthe third fastener opening 130′ and the fourth fastener opening 140′ arealigned along the second axis 128′ such that second axis 128′ passesthrough at least a portion of the fastener openings 130′, 140′. Each ofthe third fastener opening 130′ and the fourth fastener opening 140′extend from the first surface 112′ of the second portion 110′ to thesecond surface 114′ of the second portion 110′. The third fasteneropening 130′ and the fourth fastener opening 140′ each have a firstsection 132′, 142′ with a first diameter 134′, 144′ and a second section136′, 146′ with a second diameter 138′, 148′ that is smaller than thefirst diameter 134′, 144′. The first section 132′, 142′ of each fasteneropening 130′, 140′ is closer than the second section 136′, 146′ to thefirst surface 112′ of the second portion 110′. Because the firstdiameters 134′, 144′ are larger than the second diameters 138′, 148′,the intersection of the first section 132′, 142′ and the second section136′, 146′ of each fastener opening 130′, 140′ forms a lip 139′, 149′.

The first diameters 134, 144, 134′, 144′ of the first 130, second 140,third 130′, and fourth fastener openings 140′ are sized such that thehead 152 of a fastener 150 is able to be disposed within the firstsection 132, 142, 132′, 142′. The second diameters 138, 148, 138′, 148′of the first 130, second 140, third 130′, and fourth fastener openings140′ are large enough such that the shaft 154 of a fastener 150 is ableto be disposed within the second section 136, 146, 136′, 146′ but aresmall enough such that the head 152 of the fastener 150 cannot passthrough the second section 136, 146, 136′, 146′. When a fastener 150 isfully inserted into a fastener opening 130, 140, 130′, 140′, the head152 of the fastener 150 can abut the lip 139, 149, 139′, 149′ of thefastener opening 130, 140, 130′, 140′.

The first portion 110, the second portion 110′, and the bridge 160 ofthe plate 100 shown in FIGS. 1A and 1B can optionally made of aMolybdenum-Rhenium (MoRe) alloy, for example, Mo47.5Re. A MoRe alloy canbe chosen as the material for the plate 100 because of its superiorstrength as compared to other medical grade alloys. The strength of MoReallows for the manufacturing of an anterior cervical fixation plate 100with smaller overall dimensions than anterior cervical fixation platemanufactured from other materials. Although the plate 100 shown in FIGS.1A and 1B is made of Mo47.5Re, in other implementations, the plate ismade of any material at least 40 weight percent Rhenium (Re). In someimplementations, the plate is made of a Titanium-Molybdenum (TiMo)alloy, such as Ti45Mo. In some implementations, the plate is made of aCobalt-Chromium (CoCr) alloy. In some implementations, the plate is madeof a Titanium alloy. Additional medical grade alloys are describedbelow.

In the plates 100 described herein, the bridge width 180 is smaller thanthe plate width 182. This results in definition of windows 170, 172,which allow the physician to see the intervertebral space between thetwo vertebrae 198. For example, the bridge width 180 of the plate 100shown in FIGS. 1A and 1B is 4.3 mm. In other implementations, the bridgewidth can be between about 3.5 mm and 5.5 mm (e.g., 3.50 mm, 3.51 mm,3.52 mm . . . 5.48 mm, 5.49 mm, 5.50 mm) and any value or rangetherebetween. The plate width 182 of the plate 100 shown in FIGS. 1A and1B is 14.3 mm, but in other implementations, the plate width can be anywidth greater than the bridge width. This disclosure contemplates thatthe minimum plate width 182 is about 12 mm, which is limited by the sizeof the fasteners. Accordingly, the plate width 182 can be between about12 mm and 14.3 mm (e.g., 12.00 mm, 12.01 mm, 12.02 mm . . . 14.28 mm,14.29 mm, 14.30 mm) and any value or range therebetween.

The plate 100 also has a maximum thickness 184 defined as the largest ofa distance from the first surface 112 of the first portion 110 to thesecond surface 114 of the first portion 110, a distance from the firstsurface 112′ of the second portion 110′ to the second surface 114′ ofthe second portion 110′, or a distance from the first surface 162 of thebridge 160 to the second surface 164 of the bridge 160. The thickness ofthe first portion 110, the second portion 110′, and the bridge 160 ofthe plate 100 shown in FIGS. 1A and 1B are all equal, but in otherimplementations, each of the first portion, the second portion, and thebridge can be different thicknesses. The thickness of each of the firstportion 110, the second portion 110′, and bridge 160 of the plate 100shown in FIGS. 1A and 1B is 1.5 mm, and thus, the maximum thickness 184of the plate 100 is 1.5 mm. However, in other implementations, themaximum thickness is 2 mm or less. Accordingly, the thickness 184 can bebetween about 1.5 mm and 2 mm (e.g., 1.50 mm, 1.51 mm, 1.52 mm . . .1.98 mm, 1.99 mm, 2.00 mm) and any value or range therebetween.

Before the plate 100 is affixed to a spine 196, a physician must retractthe tissue from the portion of the spine 196 to which the plate will beaffixed. The retraction of tissue can lead to issues such as dysphagia,increased surgical time, and long recovery times. Thus, it is preferredthat the plate 100 be as small as possible in all dimensions such thatthe necessary amount of retraction of tissue is kept to a minimum. Thesmaller dimensions of the plates 100 described herein, therefore, helpto prevent complications in surgeries for fixating portions of acervical spine to facilitate bone fusion.

Furthermore, the plates 100 described herein provide for a narrowerbridge 160 than the plates of the prior art. Over time, osteophytes formand grow at the base of the vertebral bodies 198 of the spine 196.Before a plate 100 can be affixed to adjacent vertebral bodies 198, theosteophytes formed on the vertebral bodies 198 must be removed so thatthe plate 100 can be disposed on a relatively flat surface on theanterior surface of the cervical spine 196. This removal of osteophytescan lead to longer surgical times and longer recovery for the patient.Because the bridge 160 of the plates 100 described herein are narrowerthan those of existing plates, and the bridge 160 of the plate 100 spansthe base of the vertebral body 198 where osteophytes form, lessosteophyte removal is necessary to form a flat surface to which to affixthe plate 100. Thus, the anterior cervical fixation plates 100 describedherein provide for a plate 100 that can be implanted in less time withless future complications and a shorter average recovery time.

FIGS. 2A and 2B show another implementation of an anterior cervicalfixation plate 200 for fixating portions of a cervical spine tofacilitate bone fusion. The plate 200 shown in FIGS. 2A and 2B issimilar to the plate 100 shown in FIGS. 1A and 1B, but the plate 200shown in FIGS. 2A and 2B also includes a second bridge 260′ and a thirdportion 210″. This disclosure contemplates that the first portion 210can attach at a first level (e.g., a first vertebral body), the secondportion 210′ can attach at a second level (e.g., a second vertebralbody), and the third portion 210″ can attach at a third level (e.g., athird vertebral body). Additionally, the bridge 160 connects the firstand second portions 210, 210′, and the second bridge 260′ connects thesecond and third portions 210′, 210″. The plate 200 can accommodate sixfasteners 250, e.g., two per level or two per vertebral body.

The third portion 210″ of the plate 200 has a first surface 212″ and asecond surface 214″ opposite and spaced apart from the third surface212″. The third portion 210″ also has a first side 220″, a second side222″ opposite and spaced apart from the first side 220″ of the thirdportion 210″, a third side 224″, and a fourth side 226″ opposite andspaced apart from the third side 224″ of the third portion 210″. Thefirst 220″, second 222″, third 224″, and fourth sides 226″ extendbetween the first surface 212″ and the second surface 214″. The thirdportion 210″ further includes a third axis 228″ extending from thecenter of the third side 224″ of the third portion 210″ to the center ofthe fourth side 226″ of the third portion 210″.

The plate 200 includes a first bridge 260, similar to the bridge 160included in the plate 100 shown in FIGS. 1A and 1B, and a second bridge260′. The second bridge 260′ has a first surface 262′ and a secondsurface 264′ opposite and spaced apart from the first surface 262′ ofthe second bridge 260′. The second bridge 260′ also has a first side266′ and a second side 268′ opposite and spaced apart from the firstside 266′ of the second bridge 260′. The second bridge 260′ is centrallylocated between the second portion 210′ and the third portion 210″, andthe first side 266′ and the second side 268′ of the second bridge 260′each extend from the second side 222′ of the second portion 210′ to thefirst side 220″ of the third portion 210″.

A portion of the second side 222′ of the second portion 210′, a portionof the first side 220″ of the third portion 210″, and the first side266′ of the second bridge 260′ define a third window 270′, and a portionof the second side 222′ of the second portion 210′, a portion of thefirst side 220″ of the third portion 210″, and the second side 268′ ofthe second bridge 260′ define a fourth window 272′.

The first surface 212″ of the third portion 210″ defines a fifthfastener opening 230″ and a sixth fastener opening 240″. Each of thefifth fastener opening 230″ and the sixth fastener opening 240″ arealigned along the third axis 228″ such that third axis 228″ passesthrough at least a portion of the fastener openings 230″, 240″. Each ofthe fifth fastener opening 230″ and the sixth fastener opening 240″extend from the first surface 212″ of the third portion 210″ to thesecond surface 214″ of the third portion 210″. The fifth fasteneropening 230″ and the sixth fastener opening 240″ each have a firstsection 232″, 242″ with a first diameter 234″, 244″ and a second section236″, 246″ with a second diameter 238″, 248″ that is smaller than thefirst diameter 234″, 244″. The first section 232″, 242″ of each fasteneropening 230″, 240″ is closer than the second section 236″, 246″ to thefirst surface 212″ of the third portion 210″. Because the firstdiameters 234″, 244″ are larger than the second diameters 238″, 248″,the intersection of the first section 232″, 242″ and the second section236″, 246″ of each fastener opening 230″, 240″ forms a lip 239″, 349″.

Although FIGS. 1A and 1B show a plate 100 including two portions 110,110′ and one bridge 160, and FIGS. 2A and 2B show a plate 200 includingthree portions 210, 210′, 210″ and two bridges 260, 260′, in otherimplementations, a plate has any number of portions with bridgesextending between each set of adjacent portions.

FIG. 3 shows the plate 100 of FIG. 1 affixed to a spine 196. As seen inFIG. 3, the fasteners 150 are in a converging orientation such that thetips 156 of the fasteners 150 are closer to each other than the heads152 of the fasteners 150 are to each other. FIG. 4 also shows the plate100 of FIG. 1 affixed to a spine 196. However, in FIG. 4, the fasteners150 are in a diverging orientation such that the tips 156 of thefasteners 150 are further from each other than the heads 152 of thefasteners 150 are to each other.

It has been shown that when the fasteners 150 in an anterior cervicalfixation plate 100 are in a diverging orientation, the fasteners 150 areless likely to pull out of the spine 196 than if the same fasteners 150were oriented in the same plate 100 in the converging orientation.However, the width of many of the existing anterior cervical fixationplates cause the fastener openings in the plates to be too far apartfrom each other, which causes the heads of the fasteners to be too farfrom each other. Because the heads of the fasteners are so far apartfrom each other in many existing plates, the physician installing theplate on the spine of a patient risks the tips of the fastenerspuncturing an artery, a vein, or a nerve if the plate is installed withthe fasteners in the diverging orientation. Thus, many of the fasteneropenings of existing anterior cervical fixation plates are structured toprevent the fasteners from being oriented in a diverging orientation.However, as seen in FIG. 4, the plate width 182 of the anterior cervicalfixation plates 100 described herein are narrow enough such that thereis no risk of the tips 156 of the fasteners 150 puncturing an artery, avein, or a nerve. The fastener openings 130, 140, 130′, 140′ of theplates 100 disclosed herein are designed with large enough firstdiameters 134, 144, 134′, 144′ and second diameters 138, 148, 138′, 148′such that the fasteners 150 affixing the plate 100 to the spine 198 of apatient can be oriented in either the converging orientation or thediverging orientation.

FIGS. 5A and 5B show a detailed view of the anterior cervical fixationplate 100 of FIGS. 1A and 1B including an anti-backout device 190. Theanti-backout device 190 has a body 192 and four locking tabs 194extending radially from the body 192. The body 192 is rotatably coupledto the first surface 162 of the bridge 160, and the anti-backout device190 is rotatable relative to the bridge 160 from a first position (shownin FIG. 5A) to a second position (shown in FIG. 5B). The locking tabs194 are structured such that, when the anti-backout device 190 is in thefirst position, none of the four locking tabs 194 are covering anyportion of the first 130, second 140, third 130′, or fourth fasteneropenings 140′. After the anti-backout device 190 has been rotated fromthe first position to the second position, each of the four locking tabs194 is at least partially covering one of the four fastener openings130, 140, 130′, 140′ such that the locking tabs 194 are in a position toprevent the fasteners 150 disposed in each of the four fastener openings130, 140, 130′, 140′ from coming out of the fastener's 150 respectivefastener opening 130, 140, 130′, 140′ (also called “backing out”). Whena plate 100 is affixed to a spine 196 by driving fasteners 150 througheach of the fastener openings 130, 140, 130′, 140′ and into thevertebrae 198 of the patient, the anti-backout device 190 can be rotatedto the second position to prevent the fasteners 150 from backing out ofthe spine 196.

FIGS. 2A and 2B shows an implementation of an anti-backout device 290including only two locking tabs 294 extending from the body 292. Thus,the anti-backout devices 290 shown in FIGS. 2A and 2B are each used forpreventing the fasteners 250 disposed in only two fastener openings frombacking out. Because there are six total fastener openings 230, 240,230′, 240′, 230″, 240″ in the plate 200 shown in FIGS. 2A and 2B, theplate 200 includes three anti-backout devices 290. However, in otherimplementations, a plate can include any number of anti-backout deviceshaving any number of locking tabs for covering any number of fasteneropenings defined by the plate. In some implementations, the plateincludes one anti-backout device for each fastener opening defined bythe plate, and each anti-backout device has only one locking tab forcovering one fastener opening. In some implementations, a locking tab ofthe anti-backout device covers two or more fastener openings in thesecond position.

This disclosure contemplates that the devices described herein can bemade using alternative medical grade materials. In some implementations,the device can be made of a molybdenum-rhenium (MoRe) alloy. Optionally,the MoRe alloy is Mo47.5Re. Alternatively, the alloy is optionally99.99% pure with at least 40 weight percent (wt %) rhenium. Optionally,the alloy is optionally 99.99% pure with between 40 wt % and 99.9 wt %rhenium (e.g., 40.0 wt %, 40.01 wt %, 40.02 wt % . . . 99.88 wt %, 99.89wt %, 99.9 wt %) and any value or range therebetween. In otherimplementations, the device can be made of titanium (Ti). In otherimplementations, the device can be made of a titanium-molybdenum (TiMo)alloy including, but not limited to, Ti-15Mo. In other implementations,the device can be made of a titanium (Ti) alloy. In otherimplementations, the device can be made of a cobalt-chromium (CoCr)alloy. Other example alloys that can be used are described, for example,in U.S. 2019/0008995, published Jan. 10, 2019, titled “Molybdenum Alloysfor Medical Devices,” the disclosure of which is expressly incorporatedherein by reference in its entirety.

A number of implementations have been described. Nevertheless, it willbe understood that various modifications may be made without departingfrom the spirit and scope of the claims. Accordingly, otherimplementations are within the scope of the following claims.

Certain terminology is used herein for convenience only and is not to betaken as a limitation on the present claims. In the drawings, the samereference numbers are employed for designating the same elementsthroughout the several figures. A number of examples are provided,nevertheless, it will be understood that various modifications can bemade without departing from the spirit and scope of the disclosureherein. As used in the specification, and in the appended claims, thesingular forms “a,” “an,” “the” include plural referents unless thecontext clearly dictates otherwise. The term “comprising” and variationsthereof as used herein is used synonymously with the term “including”and variations thereof and are open, non-limiting terms. Although theterms “comprising” and “including” have been used herein to describevarious implementations, the terms “consisting essentially of” and“consisting of” can be used in place of “comprising” and “including” toprovide for more specific implementations and are also disclosed.

What is claimed is:
 1. An anterior cervical fixation plate for fixating portions of a cervical spine to facilitate bone fusion, the plate comprising: a first portion having a first surface, a second surface opposite and spaced apart from the first surface of the first portion, a first side, a second side opposite and spaced apart from the first side of the first portion, a third side, a fourth side opposite and spaced apart from the third side of the first portion, and a first axis extending from the third side of the first portion to the fourth side of the first portion, wherein the first surface of the first portion defines a first fastener opening and a second fastener opening, each of the first fastener opening and the second fastener opening being aligned along the first axis, wherein each of the first fastener opening and the second fastener opening extend from the first surface of the first portion to the second surface of the first portion; a second portion having a first surface, a second surface opposite and spaced apart from the first surface of the second portion, a first side, a second side opposite and spaced apart from the first side of the second portion, a third side, a fourth side opposite and spaced apart from the third side of the second portion, and a second axis extending from the third side of the second portion to the fourth side of the second portion, wherein the first surface of the second portion defines a third fastener opening and a fourth fastener opening, each of the third fastener opening and the fourth fastener opening being aligned along the second axis, wherein each of the third fastener opening and the fourth fastener opening extend from the first surface of the second portion to the second surface of the second portion; and a bridge having a first surface, a second surface opposite and spaced apart from the first surface of the bridge, a first side, and a second side opposite and spaced apart from the first side of the bridge, wherein the bridge is centrally located between the first portion and the second portion, and the first side and the second side of the bridge each extend from the second side of the first portion to the first side of the second portion, wherein the second side of the first portion, the first side of the second portion, and the first side of the bridge define a first window, and wherein the second side of the first portion, the first side of the second portion, and the second side of the bridge define a second window, wherein the bridge has a bridge width from the first side of the bridge to the second side of the bridge, the bridge width being about 4.3 mm or less.
 2. The plate of claim 1, wherein each of the first, second, third, and fourth fastener openings have a first section having a first diameter and a second section having a second diameter, the first section being closer than the second section to a respective first surface of the first or second portion, wherein the first diameter is greater than the second diameter.
 3. The plate of claim 2, wherein the first diameter and the second diameter allows for disposing of a fastener through each of the fastener openings such that the fastener is in a diverging orientation when the plate is affixed to portions of a cervical spine.
 4. The plate of claim 2, wherein the first diameter and the second diameter allows for disposing of a fastener through each of the fastener openings such that the fastener is in a converging orientation when the plate is affixed to portions of a cervical spine.
 5. The plate of claim 1, wherein the plate has a thickness defined as the largest of a distance from the first surface of the first portion to the second surface of the first portion, a distance from the first surface of the second portion to the second surface of the second portion, or a distance from the first surface of the bridge to the second surface of the bridge, the thickness being about 2 mm or less.
 6. The plate of claim 1, wherein the plate has a plate width defined as the largest of a distance from the third side of the first portion to the fourth side of the first portion or a distance from the third side of the second portion to the fourth side of the second portion, the plate width being about 14.3 mm or less.
 7. The plate of claim 1, further comprising an anti-backout device coupled to the first surface of the bridge, the anti-backout device being movable from a first position to a second position, wherein the anti-backout device is not covering the first fastener opening in the first position, wherein the anti-backout device is covering a portion of the first fastener opening in the second position.
 8. The plate of claim 7, wherein the anti-backout device is not covering the second fastener opening in the first position, wherein the anti-backout device is covering a portion of the second fastener opening in the second position.
 9. The plate of claim 8, wherein the anti-backout device is not covering the third fastener opening or the fourth fastener opening in the first position, wherein the anti-backout device is covering a portion of the third fastener opening and fourth fastener opening in the second position.
 10. The plate of claim 1, wherein the plate comprises a molybdenum-rhenium (MoRe) alloy.
 11. The plate of claim 10, wherein the MoRe alloy is Mo47.5Re.
 12. The plate of claim 10, wherein the plate comprises at least 40 weight percent rhenium (Re).
 13. The plate of claim 1, wherein the plate comprises a titanium-molybdenum (TiMo) alloy.
 14. The plate of claim 1, wherein the plate comprises a cobalt-chromium (CoCr) alloy.
 15. The plate of claim 1, wherein the plate comprises a titanium (Ti) alloy.
 16. An anterior cervical fixation plate for fixating portions of a cervical spine to facilitate bone fusion, the plate comprising: a first portion having a first surface, a second surface opposite and spaced apart from the first surface of the first portion, a first side, a second side opposite and spaced apart from the first side of the first portion, a third side, a fourth side opposite and spaced apart from the third side of the first portion, and a first axis extending from the third side of the first portion to the fourth side of the first portion, wherein the first surface of the first portion defines a first fastener opening and a second fastener opening, each of the first fastener opening and the second fastener opening being aligned along the first axis, wherein each of the first fastener opening and the second fastener opening extend from the first surface of the first portion to the second surface of the first portion; a second portion having a first surface, a second surface opposite and spaced apart from the first surface of the second portion, a first side, a second side opposite and spaced apart from the first side of the second portion, a third side, a fourth side opposite and spaced apart from the third side of the second portion, and a second axis extending from the third side of the second portion to the fourth side of the second portion, wherein the first surface of the second portion defines a third fastener opening and a fourth fastener opening, each of the third fastener opening and the fourth fastener opening being aligned along the second axis, wherein each of the third fastener opening and the fourth fastener opening extend from the first surface of the second portion to the second surface of the second portion; and a bridge having a first surface, a second surface opposite and spaced apart from the first surface of the bridge, a first side, and a second side opposite and spaced apart from the first side of the bridge, wherein the bridge is centrally located between the first portion and the second portion, and the first side and the second side of the bridge each extend from the second side of the first portion to the first side of the second portion, wherein the plate has a thickness defined as the largest of a distance from the first surface of the first portion to the second surface of the first portion, a distance from the first surface of the second portion to the second surface of the second portion, or a distance from the first surface of the bridge to the second surface of the bridge, the thickness being about 2 mm or less, wherein the bridge has a bridge width from the first side of the bridge to the second side of the bridge, the bridge width being about 4.3 mm or less.
 17. The plate of claim 16, wherein the plate has a plate width defined as the largest of a distance from the third side of the first portion to the fourth side of the first portion or a distance from the third side of the second portion to the fourth side of the second portion, the plate width being about 14.3 mm or less.
 18. An anterior cervical fixation plate for fixating portions of a cervical spine to facilitate bone fusion, the plate comprising: a first portion having a first surface, a second surface opposite and spaced apart from the first surface of the first portion, a first side, a second side opposite and spaced apart from the first side of the first portion, a third side, a fourth side opposite and spaced apart from the third side of the first portion, and a first axis extending from the third side of the first portion to the fourth side of the first portion, wherein the first surface of the first portion defines a first fastener opening and a second fastener opening, each of the first fastener opening and the second fastener opening being aligned along the first axis, wherein each of the first fastener opening and the second fastener opening extend from the first surface of the first portion to the second surface of the first portion; a second portion having a first surface, a second surface opposite and spaced apart from the first surface of the second portion, a first side, a second side opposite and spaced apart from the first side of the second portion, a third side, a fourth side opposite and spaced apart from the third side of the second portion, and a second axis extending from the third side of the second portion to the fourth side of the second portion, wherein the first surface of the second portion defines a third fastener opening and a fourth fastener opening, each of the third fastener opening and the fourth fastener opening being aligned along the second axis, wherein each of the third fastener opening and the fourth fastener opening extend from the first surface of the second portion to the second surface of the second portion; and a bridge having a first surface, a second surface opposite and spaced apart from the first surface of the bridge, a first side, and a second side opposite and spaced apart from the first side of the bridge, wherein the bridge is centrally located between the first portion and the second portion, and the first side and the second side of the bridge each extend from the second side of the first portion to the first side of the second portion, wherein the bridge has a bridge width from the first side of the bridge to the second side of the bridge, the bridge width being about 4.3 mm or less. 